<!--
 * @Author: error: error: git config user.name & please set dead value or install git && error: git config user.email & please set dead value or install git & please set dead value or install git
 * @Date: 2023-03-18 22:53:59
 * @LastEditors: error: error: git config user.name & please set dead value or install git && error: git config user.email & please set dead value or install git & please set dead value or install git
 * @LastEditTime: 2023-03-19 17:23:25
 * @FilePath: \从0到1的楷楷\从0到1的楷楷\pink系列\Javasritp\第四天\js\06-函数参数-默认参数.html
 * @Description: 这是默认设置,请设置`customMade`, 打开koroFileHeader查看配置 进行设置: https://github.com/OBKoro1/koro1FileHeader/wiki/%E9%85%8D%E7%BD%AE
-->
<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>

  <script>
    // 函数求和
    // function getSum(x = 0, y = 0) {
    //   // x = 1
    //   // num1 默认的值 undefined
    //   document.write(x + y)
    // }
    // getSum(1, 2)
    // getSum()  // 0
    function getSum(start = 0, end = 0) {   // end = 50
      // 形参  形式上的参数
      // console.log(end)
      let sum = 0
      for (let i = start; i <= end; i++) {
        sum += i
      }
      console.log(sum)
    }
    getSum(1, 50)  // 调用的小括号里面 实参 - 实际的参数
    getSum(100, 200)  // 实参 - 实际的参数
    getSum()
  </script>
</body>

</html>